Wood treating and preserving composition



ED. ATES PATENT o fractions of I .5

Coal tar volatility are selected'for l variations in treating pressures and temperatures.

Patented 001:.24, 1939 WOOD TREAT FFiQE.

IN G AND PRE SERVING COMIOSITION Howard B. Carpenter, Elizabeth, N. J., assignor to Penola, Inc.

No Drawing. Application October 8, 1935,

Serial No. 44,057

. 6 Claim. This invention re'latesfto improved coal tar compositions, and more particularly to compositions containing coal'tar dissolved in selected treatment and preservation of wood.

petroleum oil and suitable for the It is common practice to use creosote, a distillate fraction of tar, for Wood impregnation.

and the heavier residual fractions -thereof*have also been suggested for this use but are generally considered less desirable than creosote on account of their higher viscosity and lower toxicity. Attempts to reduce the vis of coal oil-fractions are the low solubility of coal tar in these oils.

cosity 'tar by dilution with ordinary petroleum generally unsuccessful, due to It has now been discovered that coal tar is readily soluble] in line point below compositions containing such oils are high fective for the treatment petroleum oils having an aniabout 509*F. and that coal tar ly efand preservation of wood. on-fractions of suitable viscosity and/or the-coal tar composition the particular use of derived. Volatile oils may be used as solvents for coal tar in the preparation of surface coating For exampl compositions, such as coal tar paints and varnishes.

e, pe-

troleum oils of such low aniline points and boiling below about 400 to 450 oils of. even higher boiling I-Iigher boiling oils, boiling F., are usedrin 'the preparation of coal'tar positions wood;

range may be F. are suitable, and

used.

generally above 400 CODI- tobe "used for'the impregnation of In preparing wood preservatives suitable for use as a creosote substitute for impregnating Wood; the petroleum oils used should have a flash point above about 150 'F., and preferably about 200 F., and an aniline point below 50 F., and preferably below about 20 F. oils should also have a sufliciently low vis so that the viscosity" of the above about The cosity resulting blend with coal tar issuitable for wood impregnation, for "example, about 25 to 45 seconds Saybolt at 210 F. This is given merely as an illustration of a suitable range, as wide variations in the vis of the treating medium are permissible in cosity Wood impregnation, and can be offset by suitable Viscosities of about to 40 are preferred.

Such

cracking, or destructive hydrogenation or t suitable combination of these treatments.

oils used are preferably from a. largely are 0 any The matic terial.

or naphthenic source, such as the California and V asphalt-base crudes.

A suitable method of preparing oil fractions for the present invention is to separate from a petroleum oil or fraction thereof the aromatic,

and fractions thereof to destructive hydrogena-.

tion under conditions favoring the formation of aromatic hydrocarbons.

It is known that petroleum distillates may be hydroformed by destructive hydrogenation at elevated temperatures and pressures to produce products essentially different from those produced by simple hydrogenation or even by destructive hydrogenation at lower temperatures. For example, the hydroformed products when used as motor fuels possess anti-knocking characteristics to a much greater degree than shown by the original oils or by products of other types of hydrogenation. These hydroformed products are produced from petroleum distillates such as burning oil and gas oil and in general from petroleum oils of a boiling range including that of gasoline and extending up to about 650 to 700 F. or somewhat higher. These distillate oils are passed in vapor phase with free hydrogen o-ver suitable catalysts at a or higher and at a temperature above about 900 F. and preferably within the range of about 930 to 1050 F. with a suitable partial pressure of hydrogen and time of contact to secure a destructive hydrogenation without the formation of appreciable amounts of polymerized or coky ma- The hydrogen supplied is preferably within the range of about 1000 to 4000 cubic feet per barrel of depending upon the gravity and boiling range of the charging stock. A greater proportion of hydrogen may be used with suitable variation in feed rate, temperature and pressure as is known in the art. The feed rate depends upon the reaction temperature, and other operating conditions such as the partial pressure of hydrogen and may be suitably about 1.5 to 4 volumes of oil per volume of catalyst filled reaction space per hour. The catalysts preferably compressure in excess of 20 at-, mospheres and preferably 50 to 200 atmospheres feed oil, the amount generally r residue, constituting for the coal tar, the petroleum oil 2 prise the oxides or sulfides of the metals of group VI of the periodic table with suitable promoters of the alkaline earth or earth oxides. Such catalysts are insensitive to sulfur poisoning and are suitably classified as sulfactive.

This destructive hydrogenation process is conveniently described as a hydroforming process and the liquid products thereof are identified as hydroformed products for the purpose of this invention and the claims.

A preferred oil for use according to the present invention is obtained by hydroforming extracts obtained by treating petroleum oils with selective solvents, such as liquid sulfur dioxide.

The following examples are presented to illustrate a preferred modification of this invention, but are not intended in any wayto constitute a limitation thereof.

Example 1 The extract obtained on treating a kerosene distillate fraction of a naphthenic crude oil with liquid sulfur dioxide is heated to remove 40% of the more volatile components as distillate. The 60% of the sulfur dioxide extract, is subjected to destructive hydrogenation at a temperature between 930 and 1050 F., and a pressureof 3000 lbs. per square inch in the presence of catalysts containing oxides and/ or sulfides of metals of group VL Theresullting hydro-formed liquid product is distilled to recover as distillate fractions boiling below about Forty parts by volume of the residual fraction are mixed with sixty parts of a tar consisting of the non-aqueous portion of the liquid distillate obtained by the carbonization ofbituminous coal. The resulting mixture is a substantially homogeneous liquid and shows at most'only atrace (less than 1%) of insoluble material.

The characteristics of the hydroformed oil, the coal tar and the resulting mixture are given in the following table;

Distillation* Oil Coal Tar Mixture Below 410 F 0.0 5. 8 2. 4 410 to 455 12.0 12.0 12.3 455 to 518 68.0 5. 7 24. 2 518 to 599" 19. 4 10.1 19.1 599 to 671 Trace 13.8 10; 2 Residue. Trace 52.6 31. 8 Aniline point F 70 Viscosity, sec. Saybolt 210 F 31 125(approx.) 37

*Standard Recommended Practice of American Wood-Preserversi As sociation.

If'an ordinary cracked petroleum oil fraction of similar boiling range is substituted for the .hydroformed oil in the above example, the re- .60'

sulting mixture of oil and coal tar is completely Jcoagulated into a semi-solid gel, which is'wholly unsuitable for use as a wood impregnant.

In addition to serving as a solvent and diluent fraction used in the above example also has exceptionally good a the aniline point of example for the oil point below about 50? -oil fraction of thetar and which has: an aniline 545 Distillation of Creosote, #116, Manual of preservative. qualities. Its toxicity is 0.03%, which compares favorably with an average toxicity of about 0.05% for creosote and 0.2% to 0.4% for coal tars. This toxicity, determined by the standard methodused by wood preservers, 5 is the concentration of the oil in malt-agar media necessary to completely inhibit growth of a test fungus, Fomes armosus.

The aniline point of the petroleum oil fraction used in the above example is -70 F. Such aniline points below the freezing point of aniline are determined by mixing the oil to be testedwith an oil of known high aniline point and calculating from the aniline point of the mixture, the added oil. Petroleum oils having higher aniline points of 20 and even 50 F. and of suitable viscosity, volatility and flash for the wood preservative or treating purposes desired may be substituted in the above used therein. While coal tars are often somewhat lesssoluble in theseoils of higher aniline point, the mixtures neverthetheoretical explanations or examples which; have been presented herein solely for purpose of illustration, but is limited only in the following claims, in which it is desired to claim all mates in so far as the prior art permits.

I claim: I 7, 1. An improved wood preservative composition comprising a solution of coal tar in a petroleum oil fraction which will not reduce the fungicidal & properties of ,thetar and which has an aniline F., said oil being obtained by .hydroformingf an extract of apetroleum oil having a substantial amount of ,naphth'enichydrocarbons vand which is separated fromsaid r40 petroleum oil by means of ayselective solvent;

2. -An improvedwood preservative composition comprising a solution of coaltar in a petroleum which will not, reducethe fungicidal properties point below about B. said. oil being obtained by hydroforming a sulfur. dioxide extract Ofa petroleum distillate oil fraction-'3 03. An improvedwood preservative. composition comprising a solution of a coal tar ina solvent =5 which will not reduce the fungicidal, properties .of the tar, consisting of ,ahydroformed sulfur dioxide extract of a petroleum distillate-oilffraction; said solvent having an aniline point below about 50 F. and-a flash point above about 150F. Q

4. Composition accordingtoclaimfi;in which said solvent hasan aniline point below about 5.-Composition according to claim 3,.in which said solvent has an aniline pointfof about 20 to F. and aflash point above aboutZOO. F. 6. Composition according to claim 3, having v a viscosity of about 30 to 40 seconds Saybolt" at 210F.. HOWARD, B.- cAaPn TEa; 565 

